Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783691
S. Spiessberger, M. Schiemangk, A. Sahm, A. Wicht, H. Wenzel, G. Erbert, G. Trankle
We report on the realization of a semiconductor laser based master oscillator power amplifier (MOPA) system with high output power and narrow linewidth. The system features an output power of more than 1W in stable single mode operation. The FWHM linewidth is 100 kHz and the minimum intrinsic linewidth is as small as 3.6 kHz. The laser concept presented here may find application in coherent optical communication, specifically in space, or within future precision spectroscopy and quantum optics experiments in harsh environments.
{"title":"1W narrow linewidth semiconductor based laser module emitting near 1064 nm for the use in coherent optical communication in space","authors":"S. Spiessberger, M. Schiemangk, A. Sahm, A. Wicht, H. Wenzel, G. Erbert, G. Trankle","doi":"10.1109/ICSOS.2011.5783691","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783691","url":null,"abstract":"We report on the realization of a semiconductor laser based master oscillator power amplifier (MOPA) system with high output power and narrow linewidth. The system features an output power of more than 1W in stable single mode operation. The FWHM linewidth is 100 kHz and the minimum intrinsic linewidth is as small as 3.6 kHz. The laser concept presented here may find application in coherent optical communication, specifically in space, or within future precision spectroscopy and quantum optics experiments in harsh environments.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132629547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783674
Yulan Qi, T. Kurihara, S. Ando
In previous paper, we described a novel deformation sensing technology using two conjugate multi-zeros optical beams for structure health monitoring. The multi-zeros beam has a phase term called the Gouy phase shift which is changing in proportion to the propagation distance, the initial beam waist size, and the order of the LG beam. We consider the effect of this phase term on the multi-zeros optical beam, and obtain a result that the +1st and −1st diffraction beams will rotate in opposite direction while preserving the profile of the multi-zeros optical beam. In this paper, rotation angle of multi-zeros beam in free space and transformation of it by lens are formulated quantitatively. Some results of numerical simulation are shown.
{"title":"Remote full-axis deformation sensing using multi-zeros optical beam: Interference of two multi-zeros beam","authors":"Yulan Qi, T. Kurihara, S. Ando","doi":"10.1109/ICSOS.2011.5783674","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783674","url":null,"abstract":"In previous paper, we described a novel deformation sensing technology using two conjugate multi-zeros optical beams for structure health monitoring. The multi-zeros beam has a phase term called the Gouy phase shift which is changing in proportion to the propagation distance, the initial beam waist size, and the order of the LG beam. We consider the effect of this phase term on the multi-zeros optical beam, and obtain a result that the +1st and −1st diffraction beams will rotate in opposite direction while preserving the profile of the multi-zeros optical beam. In this paper, rotation angle of multi-zeros beam in free space and transformation of it by lens are formulated quantitatively. Some results of numerical simulation are shown.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114850001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783717
Y. Koishi, Yoshiaki Suzuki, Tamaki Takahashi, I. Mase, M. Jibiki, Y. Hashimoto, S. Murata, T. Yamashita, K. Shiratama
This paper explains a plan of research and development of high speed optical communication technology for observed data transmission from satellites/airplanes. The amounts of data acquired on observation satellites or airplanes have become larger with the rapid improvements of resolutions of sensors. In order to transmit the vast amounts of data, a communication system that combines free space optical communication system and terrestrial optical networks is proposed. Particular communication protocol is planned to be developed to realize efficient and stable link quality under the special characteristics of free space optical link such as interruption by rain or cloud. Also digital coherent detection scheme is proposed to be implemented to the system to overcome the degradation by atmospheric scintillation. The plan includes the development of mobile onboard laser communication terminal and the demonstration experiments of the total system.
{"title":"Research and development of 40Gbps optical free space communication from satellite/airplane","authors":"Y. Koishi, Yoshiaki Suzuki, Tamaki Takahashi, I. Mase, M. Jibiki, Y. Hashimoto, S. Murata, T. Yamashita, K. Shiratama","doi":"10.1109/ICSOS.2011.5783717","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783717","url":null,"abstract":"This paper explains a plan of research and development of high speed optical communication technology for observed data transmission from satellites/airplanes. The amounts of data acquired on observation satellites or airplanes have become larger with the rapid improvements of resolutions of sensors. In order to transmit the vast amounts of data, a communication system that combines free space optical communication system and terrestrial optical networks is proposed. Particular communication protocol is planned to be developed to realize efficient and stable link quality under the special characteristics of free space optical link such as interruption by rain or cloud. Also digital coherent detection scheme is proposed to be implemented to the system to overcome the degradation by atmospheric scintillation. The plan includes the development of mobile onboard laser communication terminal and the demonstration experiments of the total system.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126116307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783655
T. Yamashita, M. Morita, M. Shimizu, D. Eto, K. Shiratama, S. Murata
The new tracking control system has been developed for Free-Space Optical Communications. It consists of the agile two-axis gimbals, the high performance fine-pointing-mechanism, the optical coarse acquisition sensor, and the optical fine tracking sensor. In the conventional tracking control systems, the two-axis gimbals is combined with the narrow range actuator for the fine pointing control, and it have the role of the coarse pointing control based on the GPS position and the body attitude. The each motion of the tracking mechanisms, therefore, is mutually disturbed by the individual control algorithms, and the obtained tracking accuracy is restricted by each motion. To improve the control performance of this two-stage type, the synchronized tracking-control system is proposed. The features of the system are the cooperative/predictive control using the each control/detective signals, and the improvement of the performance for disturbances, with the hollow-structured and rapid two-axis mirror gimbals. This control scheme is applied for the developed tracking control system, and makes it possible to achieve Free-Space Optical Communications. The paper shows the system configuration, the control algorithms and strategy for Free-Space Optical Communications, and the effect of the proposed control system by the several test results.1
{"title":"The new tracking control system for Free-Space Optical Communications","authors":"T. Yamashita, M. Morita, M. Shimizu, D. Eto, K. Shiratama, S. Murata","doi":"10.1109/ICSOS.2011.5783655","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783655","url":null,"abstract":"The new tracking control system has been developed for Free-Space Optical Communications. It consists of the agile two-axis gimbals, the high performance fine-pointing-mechanism, the optical coarse acquisition sensor, and the optical fine tracking sensor. In the conventional tracking control systems, the two-axis gimbals is combined with the narrow range actuator for the fine pointing control, and it have the role of the coarse pointing control based on the GPS position and the body attitude. The each motion of the tracking mechanisms, therefore, is mutually disturbed by the individual control algorithms, and the obtained tracking accuracy is restricted by each motion. To improve the control performance of this two-stage type, the synchronized tracking-control system is proposed. The features of the system are the cooperative/predictive control using the each control/detective signals, and the improvement of the performance for disturbances, with the hollow-structured and rapid two-axis mirror gimbals. This control scheme is applied for the developed tracking control system, and makes it possible to achieve Free-Space Optical Communications. The paper shows the system configuration, the control algorithms and strategy for Free-Space Optical Communications, and the effect of the proposed control system by the several test results.1","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130416836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783700
M. Musha, K. Nakagawa, K. Ueda
We have developed the light source for the space gravitational wave detector, DECIGO, and its pathfinder, DPF. The frequency stability of the 1 Hz/Hz1/2 at Fourier frequency around 1Hz, and output power of 10W are required as the light source for DECIGO. We will report the breadboard model of the frequency-stabilized Yb:YAG laser for DPF whose frequency is stabilized in reference to the saturated absorption of iodine molecules around 515nm, and the fiberMOPA system for DECIGO.
{"title":"Developments of the light source for DECIGO and DPF","authors":"M. Musha, K. Nakagawa, K. Ueda","doi":"10.1109/ICSOS.2011.5783700","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783700","url":null,"abstract":"We have developed the light source for the space gravitational wave detector, DECIGO, and its pathfinder, DPF. The frequency stability of the 1 Hz/Hz1/2 at Fourier frequency around 1Hz, and output power of 10W are required as the light source for DECIGO. We will report the breadboard model of the frequency-stabilized Yb:YAG laser for DPF whose frequency is stabilized in reference to the saturated absorption of iodine molecules around 515nm, and the fiberMOPA system for DECIGO.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127374944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783710
Kyung-hwan Kim, T. Higashino, K. Tsukamoto, S. Komaki
This paper proposes a Butterworth-type spectral model of optical scintillation to design a terrestrial free-space optical (FSO) link. It enables us to estimate the power spectral density (PSD) of optical scintillation in a current optical wireless channel when time zone and weather parameters, such as temperature and rainfall intensity, are given. Furthermore, we present the estimated scintillation index values based on the data analysis. We generate time-correlated Gamma random variable with the estimated spectral parameters and scintillation index, and present simulation results on optical fading characteristics such as the level crossing rate (LCR), the average fade duration (AFD), and burst error rate under each given condition.
{"title":"Optical fading analysis considering spectrum of optical scintillation in terrestrial free-space optical channel","authors":"Kyung-hwan Kim, T. Higashino, K. Tsukamoto, S. Komaki","doi":"10.1109/ICSOS.2011.5783710","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783710","url":null,"abstract":"This paper proposes a Butterworth-type spectral model of optical scintillation to design a terrestrial free-space optical (FSO) link. It enables us to estimate the power spectral density (PSD) of optical scintillation in a current optical wireless channel when time zone and weather parameters, such as temperature and rainfall intensity, are given. Furthermore, we present the estimated scintillation index values based on the data analysis. We generate time-correlated Gamma random variable with the estimated spectral parameters and scintillation index, and present simulation results on optical fading characteristics such as the level crossing rate (LCR), the average fade duration (AFD), and burst error rate under each given condition.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124434632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783683
T. Ando, E. Haraguchi, K. Tajima, Y. Hirano, T. Hanada, S. Yamakawa
This paper presents Bread Board Model (BBM) of homodyne BPSK (Binary Phase Shift Keying) receiver with an optical phase locked loop and a Doppler shifts compensator for inter satellite optical communication link. 2.5Gbps BPSK data has been demodulated with sensitivity of −49.1dBm at bit error rate of 1e-6 under initial frequency offset of +/−7.5 GHz simulated as Doppler shifts due to relative motion of each satellite.
{"title":"Homodyne BPSK receiver with Doppler shift compensation for inter satellite optical communication","authors":"T. Ando, E. Haraguchi, K. Tajima, Y. Hirano, T. Hanada, S. Yamakawa","doi":"10.1109/ICSOS.2011.5783683","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783683","url":null,"abstract":"This paper presents Bread Board Model (BBM) of homodyne BPSK (Binary Phase Shift Keying) receiver with an optical phase locked loop and a Doppler shifts compensator for inter satellite optical communication link. 2.5Gbps BPSK data has been demodulated with sensitivity of −49.1dBm at bit error rate of 1e-6 under initial frequency offset of +/−7.5 GHz simulated as Doppler shifts due to relative motion of each satellite.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117126203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783720
Y. Koyama, M. Toyoshima, Y. Takayama, H. Takenaka, K. Shiratama, I. Mase, O. Kawamoto
NICT initiated R & D activities of Small Optical Transponder (SOTA) for micro-satellites to demonstrate attractive features of optical technology. Development of the SOTA started based on the bread board model (BBM). Design review of BBM revealed the necessity of engineering model (EM) for critical technologies of 2-axes gimbal and receiving optics. Evaluation of the EM carried out and final design of the SOTA was fixed. This paper describes design progress of the SOTA.
{"title":"SOTA: Small Optical Transponder for micro-satellite","authors":"Y. Koyama, M. Toyoshima, Y. Takayama, H. Takenaka, K. Shiratama, I. Mase, O. Kawamoto","doi":"10.1109/ICSOS.2011.5783720","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783720","url":null,"abstract":"NICT initiated R & D activities of Small Optical Transponder (SOTA) for micro-satellites to demonstrate attractive features of optical technology. Development of the SOTA started based on the bread board model (BBM). Design review of BBM revealed the necessity of engineering model (EM) for critical technologies of 2-axes gimbal and receiving optics. Evaluation of the EM carried out and final design of the SOTA was fixed. This paper describes design progress of the SOTA.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115410693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783660
T. Plank, E. Leitgeb, M. Loeschnigg
New results derived from the research in the field of Free Space Optics (FSO) for the qualification of different wavelengths with reference to space applications are presented. At the beginning, a brief introduction to the FSO technology and the explanation of some performance evaluation criteria is presented. The main part deals with a thorough discussion of the different optical wavelengths used either for terrestrial as well as for near-Earth and deep space FSO links. Some optical signal propagation experiments through the atmosphere (including the recent investigations in airborne and satellite application for FSO) are also shown. Practical results of COST Action IC-0802 are implemented in the modelling of the FSO channel under deteriorating conditions like rain, snow, dust, fog, clouds and other atmospheric effects. It is intended to interconnect well-proved technologies like 850 nm and 1,064 nm wavelength with new technologies under development like 10 µm wavelength. Quantum Cascade Lasers (QCLs) are currently experiencing a strong progression. Semiconductor quantum cascade lasers can operate at various wavelengths between 3 µm up to 17 µm what makes them attractive in view of the 10 µm technology. Finally, some recent major performance improvement results obtained by employing some specific modulation and coding schemes are presented.
{"title":"Recent developments on free space optical links and wavelength analysis","authors":"T. Plank, E. Leitgeb, M. Loeschnigg","doi":"10.1109/ICSOS.2011.5783660","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783660","url":null,"abstract":"New results derived from the research in the field of Free Space Optics (FSO) for the qualification of different wavelengths with reference to space applications are presented. At the beginning, a brief introduction to the FSO technology and the explanation of some performance evaluation criteria is presented. The main part deals with a thorough discussion of the different optical wavelengths used either for terrestrial as well as for near-Earth and deep space FSO links. Some optical signal propagation experiments through the atmosphere (including the recent investigations in airborne and satellite application for FSO) are also shown. Practical results of COST Action IC-0802 are implemented in the modelling of the FSO channel under deteriorating conditions like rain, snow, dust, fog, clouds and other atmospheric effects. It is intended to interconnect well-proved technologies like 850 nm and 1,064 nm wavelength with new technologies under development like 10 µm wavelength. Quantum Cascade Lasers (QCLs) are currently experiencing a strong progression. Semiconductor quantum cascade lasers can operate at various wavelengths between 3 µm up to 17 µm what makes them attractive in view of the 10 µm technology. Finally, some recent major performance improvement results obtained by employing some specific modulation and coding schemes are presented.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123149091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783658
S. Miki, T. Yamashita, H. Terai, M. Fujiwara, M. Sasaki, Zhen Wang
We have developed a practical superconducting nanowire single photon detector (SNSPD) system with our superconducting thin films and devices fabrication, optical coupling packaging, and cryogenic technology. The SNSPD devices were fabricated from high-quality niobium nitride (NbN) ultra-thin films that were epitaxially grown on single-crystal MgO substrates, and optical cavity structure were applied for improvement of photo absorption efficiency. The SNSPD system was developed based on a compact Gifford-McMahon (GM) cryocooler, in which SNSPD can operate continuously at temperature of 2.9 K +/− 10 mK with low power consumption without any liquid cryogens. The system detection efficiencies at 1550 nm wavelength (at a 100 Hz dark count rate) were found to be 2.6% for device without optical cavity and 21% for device with optical cavity. The response speed of devices showed maximally 200 MHz with 5 × 5 mm square device, and timing jitter of 100 ps full width at a half maximum (FWHM) was observed.
{"title":"Development of practical superconducting nanowire single photon detector system with high detection efficiency","authors":"S. Miki, T. Yamashita, H. Terai, M. Fujiwara, M. Sasaki, Zhen Wang","doi":"10.1109/ICSOS.2011.5783658","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783658","url":null,"abstract":"We have developed a practical superconducting nanowire single photon detector (SNSPD) system with our superconducting thin films and devices fabrication, optical coupling packaging, and cryogenic technology. The SNSPD devices were fabricated from high-quality niobium nitride (NbN) ultra-thin films that were epitaxially grown on single-crystal MgO substrates, and optical cavity structure were applied for improvement of photo absorption efficiency. The SNSPD system was developed based on a compact Gifford-McMahon (GM) cryocooler, in which SNSPD can operate continuously at temperature of 2.9 K +/− 10 mK with low power consumption without any liquid cryogens. The system detection efficiencies at 1550 nm wavelength (at a 100 Hz dark count rate) were found to be 2.6% for device without optical cavity and 21% for device with optical cavity. The response speed of devices showed maximally 200 MHz with 5 × 5 mm square device, and timing jitter of 100 ps full width at a half maximum (FWHM) was observed.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114372013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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